Electronic devices typically make use of both analog and digital signals. An analog signal is a continuous signal which may assume any value. A digital signal is one in which may assume one of a discrete set of values. A signal may be in the form of an electrical current or a voltage. Electrical current is the measurement of the flow of electrons. Voltage may be defined as the difference between electric potential at two given points.
Electronic circuitry often includes devices for transferring analog signals into digital signals and vice versa. For example, a Digital-to-Analog Converter (DAC) may be used to transfer digital signals into analog signals. Conversely, an Analog-to-Digital Converter (ADC) may be used to transfer analog signals into digital signals.
One type of circuit which is often used when converting analog signals to digital signals is a track and hold circuit. A track and hold circuit switches between a track mode and a hold mode. While in track mode, an input signal is often fed to a storage node. When the circuit switches to hold mode, the storage node holds the value of the input signal at the time the switch occurs. This held value is then output from the track and hold circuit for the duration of time in which the circuit is in hold mode. The output signal may require amplification. However, amplification naturally consumes power and requires additional components which may require additional space on the chip holding the track and hold components.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.